The invention relates to a vapor barrier, which is arranged facing the room, for use in the thermal insulation of buildings, especially for thermal insulation procedures in new buildings and in the renovation of old buildings.
In order to reduce the carbon dioxide emission which occurs as a result of heating buildings, thermal insulation procedures are carried out in the construction of new buildings and in the renovation of old buildings. For economic reasons, which constantly have to be considered by the owner of the building, the question of cost also has to be taken into account here. Moreover, the external appearance of the building is a significant factor here which also represents a limit to what can actually be done. Thus, for example, thermal insulation procedures of this kind can be carried out only in buildings, which have a visible framework, by means of insulation layers which are located internally. An acceptable amount of moisture in the framework wood must also be ensured, especially under winter conditions, via the possible diffusion of vapor and also by the vapor barrier facing the room. In contrast to this, the moisture, which is due to rain and which penetrates through the joints between the wooden posts and the nogging, must also be able to dry out toward the inside in the summer months in order to ensure long life for the wood that is used in the framework despite the improved thermal insulation characteristics.
Similar difficulties also arise in subsequent full-rafter insulation on high-pitched roofs with a vapor-tight front covering, for example, roofing fabric on planking. Thus tests carried out by the Fraunhofer Institut fxc3xcr Bauphysik in the case where vapor barriers were applied inside with a water vapor diffusion resistance (sd value) which is less than a 10 m diffusion-equivalent air layer thickness, especially on roofs oriented toward the north, showed that the extent to which the planking dries Out in the summer is not sufficient to achieve a wood moisture situation which is harmless. Thus vapor barriers which are applied facing the room can no longer adequately carry away moisture accumulations which are caused by convection, for example.
Proceeding from these Known disadvantages, the problem for the invention is to create a vapor barrier which is arranged facing the room and which is capablexe2x80x94under different ambient conditions which are variable in usexe2x80x94of ensuring water vapor exchange between the room air and the interior of the building component which will, as extensively as possible, prevent damage by moisture to the building material that is used.
According to the invention, a vapor barrier for use in the insulation of buildings is formed from a material which has a water vapor diffusion resistance dependent on an ambient humidity. At a relative humidity of an atmosphere surrounding the vapor barrier in the region of 30% to 50%, the material has a water vapor diffusion resistance (sd-value) of 2 to 5 meters diffusion-equivalent air space width. At a relative humidity in the region of 60% to 80%, the material has a water vapor diffusion resistance (sd-value) which is  less than 1 meter diffusion-equivalent air space width.
Illustratively according to the invention, the vapor barrier is a film-forming composition capable of being sprayed or painted onto the inner walls of a room to form a film on the inner surface of the walls.
Further illustratively according to the invention, at least a second portion of the vapor barrier is comprised of a carrier material.
Additionally illustratively according to the invention, the carrier material is selected from the group consisting of particle board, chip board, oriented strand board, plywood paneling, gypsum board (standard or fiber reinforced), fiber board, cement board, cementitious wood wool board, calcium silica board, fiber insulation batts or slabs, foam insulation slabs, wall paper, carpet and cloth.
Illustratively according to the invention, the material is a film.
Further illustratively according to the invention, the film has a thickness of 10 xcexcm to 2 mm.
Additionally illustratively according to the invention, the film has a thickness of 20 xcexcm to 100 xcexcm.
Illustratively according to the invention, the material is applied as a coating to a carrier material. The carrier material is such that the characteristics of the vapor barrier are essentially provided by the coating.
Further illustratively according to the invention, the material is sandwiched between two layers of a carrier material. The carrier material is such that the characteristics of the vapor barrier are essentially provided by the coating.
Additionally illustratively according to the invention, the film is formed prior to application to an inner wall surface.
Illustratively according to the invention, the formed film has a decorative surface structure.
Further illustratively according to the invention, the formed film has a printed color pattern.
Additionally illustratively according to the invention, the film is chosen from polyamide 6, polyamide 4 or polyamide 3.
Illustratively according to the invention, the carrier material is a fiber reinforced cellulose material.
Further illustratively according to the invention, the material is a polymer coating applied to a carrier material.
Additionally illustratively according to the invention, a polymer for the polymer coating is selected from the group consisting of polyvinyl alcohol, dispersed synthetic resin, methyl cellulose, linseed oil alkyd resin, bone glue and protein derivatives.